Typewriter carriage positioning mechanism



Aug. 30, 1966 J. F. SMATHERS TYPEWRITER CARRIAGE POSITIONING MECHANISM 4 Sheets-Sheet 1 Filed Aug. 12. 1965 Ill-I JAMES F SMATHERS INVENTOR 6% M AGENT Aug. 30, 966 J. F. SMATHEIRS TYPEWRITER CARRIAGE POSITIONING MECHANISM Filed Aug. 12, 1963 4 Sheets-Sheet 2 JAMES F SMATHERS INVENTOR.

X 1- n BY AGE/VT Aug. 30, 1966 J. F. SMATHERS TYPEWRITER CARRIAGE POSITIONING MECHANISM Filed Aug. 12. 1963 4 Sheets-Sheet 5 JAMES F .SMA THE/F8 INVENTOR.

BY 2 M A! AGE/VT Aug. 30, 1966 J. F. SMATHERS TYPEWRITER CARRIAGE POSITIONING MECHANISM Filed Aug. 12, 1963 4 Sheets-Sheet 4;.

q/q /v MR Am 6 mm V. V Em n w M r n M 7 Cw AGE/VT United States Patent 3,269,511 TYPEWRITER CARRIAGE POSITIONING MECHANISM James F. Smathers, P26. Box 1060, Poughkeepsie, NX. Filed Aug. 12, 1963, Ser. No. 301,477 3 Claims. (Cl. 197-94) The present invention relates to a carriage positioning mechanism for typewriters, and more particularly to a mechanism associated with the tabulating mechanism for establishing preselected carriage positions whereby the letter-space escapement mechanism is disabled with any carriage movement initiated by actuation of the tabulation key, or with carriage movement in a return direction.

In many typewriters, any movement of the carriage in a letter-space direction other than that permitted by actuation of a character key is controlled by a fixed stop and tabulating stops carried by the carriage, the fixed stop being positioned on the frame so as to locate the carriage in proper relation to the type position and the tabulating stops being moved to a control position with movement of the carriage to a position relative to the type position and actuation of a tabulation set key. With actuation of the tabulation key, the escapement mechanism for controlling the letter-space movement of the carriage is released, thereby freeing the carriage for movement under the influence of the carriage drive spring motor. As the distance through which the carriage is free to move until the fixed stop engages the first tabulating stop in its path increases, the momentum of the carriage also increases with the result that the tabulating stop engages the fixed stop with a great force. This force results in rebound of the carriage and the continual possibility of improper re-engagement of the escapement mechanism so that the carriage ultimately comes to rest but not in the desired relation to the type position as established by the position of the tabulating stop. Such erratic and unreliable location of the carriage has been further enhanced by the use of power operated mechanisms for efiecting faster movement of the carriage in both a letter-space and carriage return direction and by the use of escapement mechanisms utilizing fine pitch ratchets in proportional letter spacing mechanisms.

Many attempts have been made to overcome this rebound efiect of the carriage, upon arresting of its movement in either direction, so as to accurately position it relative to the type position, but none has satisfactorily solved the immediate problem. In the present invention, a simple mechanism, associated with the escapement mechanism and operable in conjunction therewith only when the tabulating key or the carriage return key has been actuated, solves the above-presented problem. This is accomplished by a plate having spaced, peripheral notches that are aligned with predetermined teeth on the escape ratchet so as to permit engagement of the escape pawl with the ratchet only after the carriage has come to a fully rest position. The plate is rotatable with the escapement ratchet and slidably mounted on the same shaft. Normally, the plate is biased away from the ratchet so as not to interfere with the operation of the pawl for proportional letter spacing and movement of the carriage in the letter-space direction. However, when the tabulating key or the carriage return key is actuated for fully releasing the carriage from the escapement mechanism, the plate is moved axially toward the ratchet and retained in this position until the carriage comes to a complete stop, the escapement pawl and ratchet then being re-engaged. However, the control mechanism is not disabled with respect to the escapement mechanism until a character key is subsequently actuated. The land between the notches on the plate serves to hold an arm on the escapement pawl so the pawl cannot engage the ratchet until the tabulating stop or margin stop engages the fixed stop :and rebounds. On movement of the carriage into a final rest position with the stops in engagement, the notch permits the arm to drop drown so the pawl engages the ratchet. Then with actuation of the first character key, the plate is released and moves axially beyond the end of the pawl arm to permit unrestricted movement thereof in conjunction with the escapement mechanism.

The primary object of the invention is to provide an arrangement for accurately positioning the carriage of a typewriter when its movement in a letter-space or carriage return direction is unrestricted by the escapement mechanism.

Another object of the invention is to provide a mechanism that operates in conjunction with the actuation of the tabulating key or the carriage return key of a typewriter to accurately position the carriage with respect to the typing position upon unrestricted movement thereof in a letter-space or carriage return direction.

Still another object of the invention is to provide a mechanism that is actuated with the escapement mechanism of a typewriter to prevent re-engagement of the escapement mechanism during rebound of the carriage as it is brought to a stop at the end of its unrestricted travel in a letter-space or carriage return direction.

A further object of the invention is to provide a mechanism for accurately controlling re-engagement of the escapement mechanism after release and any unrestricted travel of the typewriter carriage in a letter-space or carriage return direction.

And yet another object of the invention is to provide a simple and eifective mechanism for ensuring accurate positioning of the carriage of a typewriter after any unrestricted travel thereof in a letter-space or carriage return direction.

These as well as other objects and advantages will be readily apparent to those skilled in the art when the description that follows is read in conjunction with the accompanying drawings. Reference is now made to the accompanying drawings wherein like reference numerals designate like parts and wherein:

FIG. 1 is a longitudinal sectional view taken through a typewriter embodying the invention;

FIG, 2 is a partial perspective view of the typewriter tabulating mechanism showing the control mechanism incorporated therein;

FIG. 3 is a partial perspective view of the end of the typewriter back rail;

FIG. 4 is a perspective view of the tabulating control mechanism;

FIG. 5 is a partial perspective view of the margin control mechanism;

FIG. 6 is a partial perspective view of the end of the typewriter back rail taken at a different angle from that shown in FIG. 3;

FIG. 7 is a diagrammatic plan view showing the holding member associated with the control mechanism;

FIG. 8 is a diagrammatic side view showing the relation of the control mechanism actuating member to the tabulating mechanism;

FIG. 9 is a vertical section through the control mechanism showing the relation of the control mechanism to the escapement pawl and the driving member therefor; and

FIG. 10 .is an enlarged detail view showing the relation of the notches on the control plate to the teeth on the escapement ratchet.

The invention for controlling the unrestricted movement of a typewriter carriage is disclosed herein in conjunction with a typewriter as shown in my US. Patent 2,904,159 to which reference will frequently be made. The escapement mechanism per so can be one such as shown in the above-mentioned patent or one similar to that disclosed in my US. Patent 2,848,091 or in my present-ly pending patent application Serial No. 155,382, filed November 28, 1961, now U.S. Patent No. 3,096,865. It is to be understood that the invention about to be described is also readily applicable to other escapement mechanisms which are currently being used in typewriters which are now commercially available.

With reference to FIG. 1, a carriage 10, which is a conventional typewrite carriage, is mounted for travel in a "horizontal direction by means of a front rail 11 and a rear rail 12 and carries .a conventional platen roll 13. A spring motor 14 is rotatably mounted on a bracket 15 and by means of a metallic tape 16, which has one end fixed to carriage 10, moves said carriage in a letter-space direction in a manner well known in the art.

The character type keys 20, only one of which is shown, are pivotally mounted at one end at 21 and guided in the slots 22 in a comb 23 which extends between the side frames. Springs 24, one for each of keys 20, maintain the keys in their normal position.

A conventional power-driven roller 25, which is driven in a well-known manner .by an electric motor not shown, is provided to drive a plurality of spring-loaded cams, generally designated by the numeral 26, one of said cams being associated with each type key 20, as is well known in the art and disclosed in my US. Patent 1,600,252. A plurality of cam levers 27, corresponding in number to said type keys, are pivotally mounted on a rod 28 with each cam lever 27 having a cam 26 pivotally mounted thereon at 30 with a spring 31 maintaining each respective cam lever and cam in proper position. A selecting pawl 32 is pivotal-1y mounted on each of cam levers 27 by means of a rivet 34 which extends through an elongated slot 33 in the pawl 32. Each of the pawls 32 is provided with a lug 36' that is maintained in abutting relation with a lug 36 on a respective key 20 by means of a spring 35 'having one end fixed to pawl 32 and the other end fixed to its respective cam lever 27. Each of the pawls is also urged toward a key 20 by a spring 31 due to engagement of each of earns 26 with a respective lug 65 on each of said pawls, thereby also serving to maintain lugs 36 and 36' in an abutting relation.

A selector comb 37 is arranged beneath a bracket 38 and with respect to a rod 39, cam stops 40 being adjustably mounted on the bracket 38. Type bars 41 are pivotally mounted at 42 in a p-ivotable comb 43 and are connected by links 44 to their corresponding cam levers 27. A rod 39 beneath comb 37 engages the underside of selectors 45 which are pivotally mounted at one end at 46 to cam levers 27 and slidably engage the slots in comb 37. Templet rods 47, 48 and 49 are mounted in a bracket 50 and carry rocker arms 51, 52 and 53 to which clevis rods 54, 55 and 56 are connected, respectively. These templet rods extend transversely of the typewriter and are disposed in intersecting planes with selectors 45 which engage a respective one of the projections 77, 78, 79 in the stepped upper edge of said templet rods. It should be noted at this point that selectors 45 are provided for keys 20 which require a spacing other than normal, in other words, more or less than three increments of space.

In operation, an operator will strike a key 20 causing it to pivot about 21 and thereby tension spring 24. At the same time, the key is guided by slot 22 in comb 23 during its movement. Lugs 36 and 36 cause pawl 32 to rotate the corresponding cam 26 in a counterclockwise direction, thereby urging cam portion 29 against the continuously rotating drive roll 25 whereby cam lever 27 is actuated and through link 44 causes type bar 41 to pivot on rod 42 and strike platen 13 to print the corresponding character. The pivoting movement of type bar 41 causes said bar to strike universal bar 57 which then shifts toward the rear of the typewriter. Cam lever 27, simultaneously with the actuation of type bar 41, draws selector 45 toward the rear of the typewriter and by means of lug 45 the latter engages a respective projection 77, 78, 79 in a corresponding templet rod 47, 48, 49 to rotate the latter in a clockwise direction. With this action the corresponding clevis rods 54, 55, 56 is moved toward the front of the typewriter. A complete disclosure of the structure and function of selector 45 and its related elements can be found in my US. Patent 2,904,159.

Clevis rods 54, 55 and 56 are connected to extensions 58, 59 and 60 on rods mounted in a bracket 61, only one of said rods, namely rod 62, being shown in FIG. 1. Similar extensions, not shown, are fixed to the other ends of said rods which, in turn, are connected by links to plates for oscillating members which are associated with the escapement mechanism and fully described in my US. Patent 2,848,091. Also, universal bar 57 is connected by a link 69 to lip 118, see FIG. 1, whereby an escapement mechanism 70 is actuated in a manner also described in the aforementioned Patent 2,848,091.

The escapement mechanism 70 is driven by means of the carriage 10. This is accomplished by means of a rack 71 which is fixed to the carriage, as shown in FIG. 1, and which meshes with a pinion 72 on the upper side of a plate 73. Pinion 72 is rotatably mounted with a ratchet 74, the teeth of which determine the increment of movement of carriage 10, as described in my abovenoted patents.

For tabulating, one or more of tabulating stops is actuated to a position in the path of lug 81 and contact end 82, in a manner as disclosed in US. Patents 2,157,- 053 and 2,854,123, the latter patent disclosing a form of tabulating stop that is substantially the same as that shown in FIG. 1. A tabulator key 83, which is arranged at one side of the keyboard in a well-known manner, is depressed causing a cam 26 to be actuated. Clevis rod 85 is secured on one end to the cam and on the other end to a control lever 86, thereby pivoting control lever 86 on a spacer 87, see FIGS. 2 and 4. Control lever 86 pivots a blade lever 88 around a stud 89 through an intermediate link 90, see FIG. 2. Blade lever 88 through intermediate lever 91 pivots a fiat lever 92 about the pivot at 93 which through a clevis rod 94 pivots a one arm lever 95 on shaft 96 and thereby swings at two arm lever 97 which abuts leg 98 of feed pawl disengaging lever 99 whereby tooth engaging finger 100 is raised out of engagement with escapement wheel teeth 75 as feed pawl disengaging lever 99 pivots around a stud 117.

Simultaneously with the action just described, the pivoting of control lever 86 causes a link 101 through pivot 102 to move toward the rear of the machine and through the spacer connected at 103 to a dog leg lever 104, the latter moves around pivot 105 so that end 115 on lever 104 pushes tabulating bar 106 to cause it to pivot sideways on stud 107 whereby lug 81 is moved toward the rear of the machine (in a counterclockwise direction as viewed in FIG. 4) into the path of tabulator stop 80. Tabulator short latch 108 under the influence of its spring 109 pivots behind tabulator bar 106 to hold it in the tabulator stop position. A tongue 110 fixed to tabulator bar 106 pivots tabulator bell crank lever 111 around its pivot (not shown) to place contact end 82 the path of tabulating stop 80. The sideways pivoting movement of tabulator bar 106 causes bar 106 to pivot tabulator latch 113 around pivotal point 114 whereby a stop thereon disengages a link to permit it to pivot, under the urging of a spring, away from the tabulator safety dog 119 to allow the tabulator safety dog to be influenced by its spring whereby a stop 180 thereof passes under the feed pawl disengaging lever 99 to latch it in position so as to maintain finger 100 disengaged from ratchet 74, as disclosed and described in my Patent 2,904,159. The escapement wheel will then be free to allow the carriage to travel under the influence of spring motor 14.

When tabulator bell crank lever 111 pivots forwardly, a latch 123 under the influence of a spring 124 pivots on stud 125 to place a projection 126 behind the lever 111 to hold it in an outward position.

The carriage 10 under the influence of the spring motor 14 carries a set tabulator stop 80 to the right, as viewed FIG. 2. The set tabulator stop 80 simultaneously strikes lug 81 and contact end 82. The impact moves the tabulator bar 106 untilstud 107 engages the left end of an elongated slot 127. Continued movement of the tabulator bar thereafter tensions a leg 128 of bracket 129 thereby absorbing the impact of the carriage and momentarily limiting its movement. As the tabulator bar 106 approaches the limit of its movement, it moves into a position in which spring 109 can move tabulator short latch 108 behind tabulator bar 106, so that at the limit of its movement, tabular bar 106 swings out of the path of the tabulator stop 80 due to the position now assumed by short latch 108. While the tabulator bar is approaching its limit, contact end 82, which also was engaged by stop 80, pivots lever 111 around a stud (not shown) thereby causing a leg extension thereof to pivot the link associated with tabulator latch 113, the stud, leg extension and link being more fully disclosed and described in my US. Patent 2,904,159, so as to force tabulator safety dog 119 downwardly, thereby freeing feed pawl disengaging lever 99 which pivots on stud 117 due to spring 116, to allow tooth engaging finger 100 to drop into engagement with a tooth 75 under the influence of the spring 116. The carriage which was momentarily stopped at the limit of motion of tabulator bar 106, now resumes its travel unimpeded by lug 81, over a very short distance which, when translated into movement of the escapement, is a distance less than the pitch of the teeth on the escapement wheel. Movement of the carriage through this short distance pivots lever 111 further, whereby it slips off latch projection 126 and under the influence of a spring 122 resumes its normal position as shown in FIG. 4. This time the carriage movement is actually arrested by engagement of finger 100 in a tooth 75 of the escapement wheel. As is apparent from the above description, the impact of the carriage upon engaging lug 81 and end 82 should be absorbed by yieldable leg or member 128 which, after absorbing the impact, is ineffective to cause carriage rebound. However, it has been found that yieldable member 128 does not negate the rebound momentum of the carriage after striking the lug 81 to completely eliminate rebound and that finger 100 will slide past one or more teeth of the escapement wheel so as to improper- 1y position the carriage relative to the typing position.

With reference to FIGS. 7-10, the shaft 150, to which the pinion 72 and the ratchet 74 are connected, carries a slidable member 151 which comprises a sleeve portion 152, a shoulder 153 and a control portion 154. The member 151 is urged toward the pinion 72 by an expansion spring 155 and is normally retained in this position. The periphery of the control portion 154 is provided with spaced teeth 156 which are equiangularly spaced about the periphery of control portion 154. The teeth 156 are formed by land portions 157 and recessed spaces 158. As shown in FIG. 10, the peripheral length of each of the land portions 157 is equivalent to substantially twice the pitch of two successive teeth 75 of the ratchet 74. On the other hand, each space 158 is of a width at the peripheral extremity that is equivalent to substantially the pitch of a single tooth on the ratchet 74. It should be noted, particularly with respect to FIG. 10, that the sides of the spaces 158 diverge from the periphery toward the shaft 150. In order that the lands 157 will retain the finger 100 positively disengaged from the ratchet 74 as described hereinafter, the diameter of the control portion 154 is slightly larger than the overall diameter of the ratchet 74.

A link 160 is pivotally mounted at 114 on the opposite side of an ear 162 on which the latch 113 is also mounted. Link 160 has one end 163 abutting the tabulating bar 106 and the other end 164 in engagement with the rear surface 165 of the control portion 154. From the above description relating to the operation of the tabulating bar 106 when the key 83 is actuated for positioning the lug 81 in the path of a tab stop 80, the link 160 is moved in a clockwise direction whereby an end 164 causes the member 151 to be moved axially in a direction toward the ratchet 74. As this occurs, a bell crank lever 166, which is normally held against the shoulder 153 under the action of a spring 167, is positioned over the shoulder 153, as shown in dotted lines in FIG. 7, to retain the member 151 in close proximity to the ratchet 74. Since member 151 is keyed or otherwise fixed to shaft 150, member 151 and ratchet 74 will rotate as a unit. As described above, ratchet 74 is released for movement by means of spring motor 14 and rack 71 which meshes with pinion 72, when finger 100 is disengaged from the teeth of ratchet 74. When this occurs, as described above with respect to actuation of tabulating key 83, the ratchet 74 and control-member 151 rotate as a unit until the tabulating stop engages the lug 81.

As pointed out hereinbefore, the release of the carriage to establish the platen in relation to the typing position, in which case the platen may be moving at a relatively high speed, the impact force with which the tab stop 80 engages the lug 81 causes a rebound of the carriage before it actually comes to an arrested position. Due to the arrangement of the teeth 156 in relation tothe teeth 75 on ratchet 74, as shown in FIG. 10, the finger is retained in a Withdrawn position by the land portion 157 on rebound and does not align with a space 158 until the tab stop 80 has come to a definite rest and engaging position with respect to lug 81. When this occurs, the finger 100 will be aligned with a space 158 and permitted to drop into engagement with the corresponding tooth of the ratchet 74. Also, as tabulating bar 106 returns to its normal position, spring 168 causes link to follow so that end 164 will permit member 151 to be moved axially by spring 155. However, since lever 166 is still in engagement with surface due to spring 167, member 151 cannot move axially to its normal position.

As described in my above-mentioned US. Patent 2,904,159, when any one of the character keys 20 is actuated, the escapement mechanism 70 is also actuated to provide movement of the carriage in accordance with the number of increments of movement required for the character key that has been actuated. At the same time that the escapement mechanism 70 is released by actuation of one of keys 20 and movement of carriage return link 145 by universal bar 57, a lever 170 that is pivotally mounted at 171 is moved by a link 172 in a clockwise direction, link 172 being pivotally connected to an arm 173 of a bell crank lever 174 which is pivotal-1y mounted at 175 and has its other arm 176 pivotally connected to link 145, as shown in FIG. 7. This movement of levers 170 and 166 with actuation of a key 20 causes the release of member 151, in that lever 166 is rotated away from shoulder 153 so :as to permit spring 155 to move member 151 in an axial direction away from ratchet 74 and to a position in which the control portion. 154 cannot be engaged by finger 100, thereby permitting the escapement mechanism to again be controlled by the successive actuation of each character key.

When the carriage 10 is to be returned under the infiuence of power, that is, by means of an electric motor not shown, a carriage return key 149 is depressed, thereby actuating one of the cams 26 which simultaneously performs two functions. One, the cam causes a clutch, not shown, to couple the carriage 10 to the electric motor. Two, by means of a clevis rod 130, the cam 26 pivots blade lever 88 around stud 89 which through a pivotal connection 131 draws the intermediate link and its fork end 132 away from a pin 133 on the control lever 86 which remains inoperative. Blade lever 88 pivots a stud 134 under a projection 135 thereby pivoting safety bumper lever 136 on stud 137 in a counterclockwise direction against le-g 138 to pivot projection 184 out of the path of travel of base 141 on margin stop 142.

By means of blade lever 88 and intermediate lever 91, flat lever 92 is moved, and through clevis rod 94, pivots lever which, in turn, pivots lever 97 that abuts leg 98, whereby feed pawl disengaging lever 99 lifts tooth engaging finger out of engagement with the teeth 75. The carriage 10 is now free to travel under the influence of the electric motor, since it is coupled thereto by the clutch previously mentioned, but not shown.

The carriage travels in a return direction, that is, to the left as seen in FIGS. 2, 4 and 5, until stop guide 143 strikes projection 144 and pulls carriage return link 145 sideways, thereby pivoting carriage return link 145 around stud 183 against the tension of spring 147. Carriage return safety dog abutment 148 is raised away from carriage return safety dog 119 which, under the influence of a spring, pivots on a stud, both of which are not shown but which are disclosed and described in my US. Patent 2,904,159, to move the stop 180, see FIG. 4, under feed pawl disengaging lever 99 into a position to hold tooth engaging finger 100 out of engagement with teeth 75. By means of surface 181, carriage return link 145 engages and pivots blade lever 88 on stud 89 and by means of a clevis rod and bell crank lever shown in my above patent, the clutch is disengaged to terminate the power return movement of the carriage. The movement of blade lever 88 by surface 181 removes stud 134 from beneath projection so that safety bumper lever 136 is free to allow a spring to pivot safety bumper link 139 on pin to place projection 184 in a position between base 141 and projection 185. The pivoting of blade lever 88 by surface 181 also pivots (in a return direction) flat lever 92 which by means of clevis rod 94 pivots one arm lever 95 and two arm lever 97 to remove the latter from engagement with leg extension 98.

As the events described above are occurring, base 141 strikes projection 185, see FIGS. 2, 4 and 5, and causes tabulating bar 106 to pivot in a counterclockwise direction due to the offset relation of base 141 with respect to projection 185 and the location of pivot stud 107, thereby rocking latch 113 and link about the pivot 114. The movement of link 160 causes end 164 thereof to move member 151 in an axial direction toward ratchet 74 so that member 151 and ratchet 74 are movable as a unit. Although the lever 99 is released upon engagement of base 141 with projection 144, the finger 100 is held out of engagement with teeth 75 by the land portion 157 on rebound and does not align with a space 158 until base 141 has come to a definite rest and engaging position with respect to projection 144. When this occurs, the finger 100 is aligned with a space 158 and permitted to drop into engagement with the corresponding tooth of the ratchet 74. As described above, when any one of keys 20 is actuated, the escapement mechanism 70 is also actuated and levers and 166 cause release of-member 151 so that the escapement mechanism is again controlled by the successive actuation of each character key.

. The control mechanism just described provides for an instant control of the tabulating stop mechanism or the carriage return mechanism in order to accurately position the platen with respect to the typing position. It will be readily apparent to those skilled in the art that the relationship of the spaces 158 of the member 151 to the teeth 75 of the ratchet 74 is of utmost importance in order to establish the proper relationship of the platen and carriage to the type position. It will also be readily apparent to those skilled in the art that this control arrangement may be varied or modified in many ways to accomplish the same result. However, the invention is not to be limited to the disclosed embodiment, but is of a scope as defined by the appended claims.

I claim:

1. In a typewriter having a plurality of character keys, a tabulating key, a carriage return key and a carriage movable in a letter-space direction relative to a typing position and in a return direction to a margin position, said carriage including a plurality of tabulating stops arranged thereon and movable selectively to a stop position for arresting uninterrupted travel of said carriage in said letter-space direction and an adjustable margin stop for arresting movement of said carriage in said return direction, drive means adapted to be coupled to said carriage for moving the latter in said letter-space direction, power means adapted to be coupled to said carriage for moving the latter in said return direction, an escapement mechanism including a ratchet and pawl and actuated by movement of one of said character keys for coupling said drive means to said carriage and for controlling the movement of said carriage in said letter-space direction in accordance with the character key that is actuated, a tabulating mechanism including a stop member and actuated by movement of said tabulating key for enabling said escapement mechanism to couple said drive means to said carriage for uninterrupted movement thereof in said letter-space direction, and a carriage return mechanism including a return stop member and actuated by movement of said carriage return key for coupling said power means to said carriage for movement thereof in said return direction, the combination comprising:

a disc provided with equiangularly spaced, peripheral notches and slidably mounted for coaxial movement into cooperating relationship with said ratchet in response to actuation of said tabulating mechanism and of said carriage return mechanism for controlling the return of said escapement mechanism to an operative condition to establish the position of said carriage relative to said typing position, thelands between successive notches serving to hold said pawl out of engagement with said ratchet until movement of said carriage in either of said letter-space direction or said return direction has been arrested;

means movable in response to engagement of said stop member and one of said tabulating stops in said stop position with uninterrupted movement of said carriage in said letter-space direction and of said return stop member and said margin stop with movement of said carriage in a return direction for holding said disc in cooperating relationship with said ratchet; and

means responsive to actuation of the first character key after movement of said carriage has been arrested for releasing said holding means to re-establish control of the movement of said carriage by i said escapement mechanism.

2. A typewriter in accordance with claim 1 wherein the notches in said disc are of a width greater than the pitch of the teeth of said ratchet and of a depth greater than said teeth whereby said pawl can engage only the teeth of said ratchet aligned with said notches.

3. A typewriter in accordance with claim 1 wherein the pitch of the teeth of said ratchet is equivalent to the 9 smallest increment of movement of said ratchet and the pitch of the notches in said disc is equivalent to the largest increment of movement of said ratchet.

References Cited by the Examiner UNITED STATES PATENTS 994,973 6/ 1911 Busch mann 197-82 1,295,212 2/1919 Rufiin 19782 2,831,558 4/1958 Toggenburber 19784.3

Dodge 197-178 Smathers 19784.3 Schremp 19784.3 Beccio 19784.3 Lambert 197-66 ROBERT E. PULFREY, Primary Examiner. DAVID KLEIN, Examiner.

E. T. WRIGHT, Assistant Examiner. 

1. IN A TYPEWRITER HAVING A PLURALITY OF CHARACTER KEYS, A TABULATING KEY, A CARRIAGE RETURN KEY AND A CARRIAGE MOVABLE IN A LETTER-SPACE DIRECTION RELATIVE TO A TYPING POSITIION AND IN A RETURN DIRECTION TO A MARGIN POSITION, SAID CARRIAGE INCLUDING A PLURALITY OF TABULATING STOPS ARRANGED THEREON AND MOVABLE SELECTIVELY TO A STOP POSITION FOR ARRESTING UNINTERRUPTED TRAVEL OF SAID CARRIAGE IN SAID LETTER-SPACE DIRECTION AND AN ADJUSTABLE MARGIN STOP FOR ARRESTING MOVEMENT AND SAID CARRIAGE IN SAID RETURN DIRECTION, DRIVE MEANS ADAPTED TO BE COUPLED TO SAID CARRIAGE FOR MOVING THE LATTER IN SAID LETTER-SPACE DIRECTION, POWER MEANS ADAPTED TO BE COUPLED TO SAID CARRIAGE FOR MOVING THE LATTER IN SAID RETURN DIRECTION, AN ESCAPEMENT MECHANISM INCLUDING A RATCHET AND PAWL AND ACTUATED BY MOVEMENT OF ONE OF SAID CHARACTER KEYS FOR COUPLING SAID DRIVE MEANS TO SAID CARRIAGE AND FOR CONTROLLING THE MOVEMENT OF SAID CARRIAGE IN SAID LETTER-SPACE DIRECTION IN ACCORDANCE WITH THE CHARACTER KEY THAT IS ACTUATED, A TABULATING MECHANISM INCLUDING A STOP MEMBER AND ACTUATED BY MOVEMENT OF SAID TABULATING KEY FOR ENABLING SAID ESCAPEMENT MECHANISM TO COUPLE SAID DRIVE MEANS TO SAID CARRIAGE FOR UNINTERRUPTED MOVEMENT THEREOF IN SAID LETTER-SPACE DIRECTION, AND A CARRIAGE RETURN MECHANISM INCLUDING A RETURN STOP MEMBER AND ACTUATED BY MOVEMENT OF SAID CARRIAGE RETURN KEY FOR COUPLING SAID POWER MEANS TO SAID CARRIAGE FOR MOVEMENT THEREOF IN SAID RETURN DIRECTIION, THE COMBINATION COMPRISING: A DISC PROVIDED WITH EQUIANGULARLY SPACED, PERIPHERAL NOTCHES AND SLIDABLY MOUNTED FOR COAXIAL MOVEMENT INTO COOPERATING RELATIONSHIP WITH SAID RATCHET IN RESPONSE TO ACTUATION OF SAID TABULATING MECHANISM AND OF SAID CARRIAGE RETURN MECHANISM FOR CONTROLLING THE RETURN OF SAID ESCAPEMENT MECHANISM TO AN OPERATIVE CONDITION TO ESTABLISH THE POSITION OF SAID CARRIAGE RELATIVE TO SAID TYPING POSITION, THE LANDS BETWEEN SUCCESSIVE NOTCHES SERVING TO HOLD SAID PAWL OUT OF ENGAGEMENT WITH SAID RATCHET UNTIL MOVEMENT OF SAID CARRIAGE IN EITHER OF SAID LETTER-SPACE DIRECTION OR SAID RETURN DIRECTION HAS BEEN ARRESTED; MEANS MOVABLE IN RESPONSE TO ENGAGEMENT OF SAID STOP MEMBER AND ONE OF SAID TABULATING STOPS IN SAID STOP POSITION WITH UNINTERRUPTED MOVEMENT OF SAID CARRIAGE IN SAID LETTER-SPACE DIRECTION AND OF SAID RETURN STOP MEMBER AND SAID MARGIN STOP WITH MOVEMENT OF SAID CARRIAGE IN A RETURN DIRECTION FOR HOLDING SAID DISC IN COOPERATING RELATIONSHIP WITH SAID RATCHET; AND MEANS RESPONSIVE TO ACTUATION OF THE FIRST CHARACTER KEY AFTER MOVEMENT OF SAID CARRIAGE HAS BEEN ARRESTED FOR RELEASING SAID HOLDING MEANS TO RE-ESTABLISH CONTROL OF THE MOVEMENT OF SAID CARRIAGE BY SAID ESCAPEMENT MECHANISM. 